It is proposed to apply a sensitive nuclear magnetic double resonance technique to measure 170-170 and 63Cu pure nuclear quadrupole resonance spectrums and internuclear distances in the oxygen binding site of the copper protein hemocyanin. The double resonance technique, which is based on spin dipolar coupling between proton and 170 (or 63Cu) spins, has already been applied at the detection of 170-170 quadropole resonances in a synthetic iridium compound which also binds reversibly one molecule of oxygen and for which the 0-0 internuclear distance is known from x-ray diffraction. Using this internuclear distance as a standard we have devised a triple resonance technique which will measure the internuclear distance between any two dipolar coupled spins whose double resonance quadrupole spectrum can be observed. If successful here, these NMR techniques will provide two independent experimental measures of electronic structure in the hemocyanin active site, (1) 170-170 and 63Cu electric field gradients, and (2) 0-0, Cu-0, and Cu-cu internuclear distances.